[Lex] over at Computing: The Details loves to make fun projects. Recently, he’s created a hardware CPU monitor that allows him to see how well his PC is parallelizing compile tasks at a glance. The monitor is built from 14 analog meters, along with some WS2812 RGB LEDs.

Each meter represents a core on [Lex]’s CPU, while the final two meters show memory and swap usage. The meters themselves are low-cost 5 mA devices. Of course, the original milliamps legends wouldn’t do much good, so [Lex] designed and printed graduations that glue over the top. The RGB LED strip is positioned so two LEDs fit under each meter. The LEDs allow a splash of color to draw attention to the current state of the machine. The whole bank going red would sure get our attention!

The system is controlled by an Arduino Mega, with the meters driven using the PWM pins. The only extra part is a 1 K resistor. The Arduino wrangles the LEDs as well. Sadly [Lex] did not include his software. He did describe it though. Basically he’s using a Rust program to call systemstat, obtaining the current CPU utilization data in Linux. A bit of math converts this into pointer values and LED colors. The data is then sent via USB-serial to the Arduino Mega. The software savvy will say it’s pretty easy to replicate, but the hardware only hackers among us might need a bit of help.

This isn’t the first custom meter we’ve seen on Hackaday. Your author’s first project covered by Hackaday was for a meter created using an automotive gauge stepper motor. I didn’t include source code either – but only because [Guy Carpenter]’s Switec X25 library had me covered.

Thanks for the tip, [TubeTime]!

Necessity might be the mother of all invention, but we often find that inventions around here are just as often driven by expensive off-the-shelf parts and a lack of willingness to spend top dollar for them. More often than not, we find people building their own tools or parts as if these high prices are a challenge instead of simply shrugging and ordering them from a supplier. The latest in those accepting the challenge of building their own parts is [Advanced Tinkering] who needed a specialty pressure gauge for a vacuum chamber.

In this specific case, the sensor itself is not too highly priced but the controller for it was the deal-breaker, so with a trusty Arduino in hand a custom gauge was fashioned once the sensor was acquired. This one uses an external analog-to-digital converter to interface with the sensor with 16-bit resolution, along with some circuitry to bring the ~8 V output of the sensor down to the 5 V required by the microcontroller. [Advanced Tinkering] wanted a custom live readout as well, so a 3D printed enclosure was built that includes both an LCD readout of the pressure and a screen with a graph of the pressure over time.

For anyone else making sensitive pressure measurements in a vacuum chamber, [Advanced Tinkering] made the project code available on a GitHub page. It’s a great solution to an otherwise overpriced part provided you have the time to build something custom. If you’re looking for something a little less delicate, though, take a look at this no-battery pressure sensor meant to ride along on a bicycle wheel.

[Wesley Kagan] is building a Corvette with a V12 engine swap. Much of the driveline will be entirely replaced, which means the components to drive the mechanical speedometer and tachometer will no longer be present in the final car. Instead, [Wesley] came up with his own electronic gauge conversion to do the job.

It’s a build that respects the original aesthetic of the car, reusing the original gauges but driving them differently. In place of the original mechanical drives from the transmission and distributor respectively, the speedometer and tach instead get servos installed in the back with a 3D printed gear train. The odometer gets its own continuous rotation servo, too. An Arduino Nano is used to drive the servos, using data from a GPS module and the car’s ignition system.

Files are available for anyone wishing to 3D print parts to modify their own gauges. We can’t wait to see how the gauges look when finally installed. We can imagine some teething problems with slew rate or update speed, but we’re sure it’s nothing [Wesley] can’t engineer out with a few revisions. Custom gauges are something we’ve seen a few times around these parts; this digital setup is particularly useful for engine data. Video after the break.

In today’s world of over-the-air firmware upgrades in everything from cars to phones to refrigerators, it’s common for manufacturers of various things to lock out features in software and force you to pay for the upgrades. Even if the hardware is the same across all the models, you can still be on the hook if you want to unlock anything extra. And, it seems as though Suzuki might be following this trend as well, as [Sebastian] found out when he opened up his 2011 Vstrom motorcycle.

The main feature that was lacking on this bike was a gear indicator. Even though all the hardware was available in the gearbox, and the ECU was able to know the current gear in use, there was no indicator on the gauge cluster. By using an Arduino paired with an OBD reading tool (even motorcycles make use of OBD these days), [Sebastian] was able to wire an LED ring into the gauge cluster to show the current gear while he’s riding.

The build is very professionally done and is so well blended into the gauge cluster that even we had a hard time spotting it at first. While this feature might require some additional lighting on the gauge cluster for Suzuki to be able to offer this feature, we have seen other “missing” features in devices that could be unlocked with a laughably small amount of effort.

Tomas Amberg shared with us the link to an Instructable he published on how to build a Web-enabled, Arduino-based IoT Gauge with a REST API, and connect it to the IFTTT mash-up platform, via the Yaler.net relay service he founded.

The cool thing about this project is the connection with the Maker Channel  of IFTTT which supports custom Webhooks, to integrate DIY IoT projects: 

Inspired by WhereDial, a DIY Internet of Things classic, the IoT Gauge shows the current location of its owner. A bit like the Weasley Clock in Harry Potter. The design and code of the IoT Gauge is generic and could be used as well to display e.g. weather conditions. The logic resides in the Cloud, the gauge is just a servo with an API.

Check out the five-step tutorial and the ingredients you need at this link.